Plaster board



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C. A. PETERS PLASTER BOARD Flled Feb 16 1925 m .www

Oct. 26 1926.

Patented Oct. 26, 1926.

UNITED STATES PATEN'I OFFICE.

'CHARLES A. PETERS, OF DOWNEY, CALIFORNIA, ASSIGNOR TO PETERS HOLDINGCOMPANY, A CORPORATION OF CALIFORNIA.

PLASTER BOARD.

Application led February This invention particularly pertains to acomposition wall board and to the method of manufacturing same.

An object of the invention is to provide a composition board which isadapted to be employed in forming surfaces of buildings and which is soformed as to provide a surface having the character of plaster to whichmay be applied either a plastic coating or the fluid coatings commonlyemployed in the finishing and decoration of plastered walls.

Another object is to provide an effective method for manufacturing awall board of the above character.

The type of wall board to which the present invention pertains embodiesa panel or slab formed of a suitable composition which, during thecourse of manufacture of the board, is of plastic character, and whichcomposition preferably includes gypsum or similar cementitious materialintermixed with a vsuitable fibrous filler preferably consisting solelyof asbestos fibers, but which 5 may be formed of any other fibers thatwill serve as a binder and reinforcement of the mass, these ingredientsbeing admixed with water to form a plaster' which hardens when dry.

The plaster panel is' surfaced on one side with a backing sheet whichmay comprise paper, as commonly employed in wall board construction(` ormay consist of a woven fabric, and the other or outer face of the. panelis formed with a fibrous foraminous or reticnlated reinforcing sheetpreferably consisting of cotton gauze of open mesh.

In carrying out the present invention, the foraminous sheet isapplied tothe surface of the plaster, preferably in such manner that the outersurface of the board will be so formed as to provide a comparativelyhard and compact shell over the foraminous sheet surface to which may beapplied any suitable finish coating.

A particular object of the invention is to provide means and for readilyforming the roughened hard shell surface of the board.

The mode of carrying out the foregoing objects, as well as such objects,features and advantages of the invention as may' subsequently appear ishereinafter described and is illustrated by way of example in theaccompanying drawings in which the several 1s, 1925. serial No. 9,608.

views depict constructions and arrangement of elements and parts wherebythe invention mav be carried into effect.

Referring to the drawings the views are as follows Figure 1 is a diagramillustrating the manner of forming the board;

Figures 2, 3, 4, 5 and 6 are details illustrating more clearlythe modeof forming the board;

Figure 7 is a detail in pla-n of a fragmentary portion of the boardshowing the roughened outer surface of the board; and

Figure 8 is a View in section of the finished board as seen on the line8-8 of Figure 7.

More specically, 10 indicates a long horizontally extending endlessconveyor belt several which passes around direction rollers 11 and- 12and is adapted to be advanced by any suitable driving mechanism as iscommon in Wall board manufacture.

A fibrous backing strip 13 of paper or similar materia-l is fed from a.roll 14 over a table 15 and between a pair of forming rollers 16 and16', and is directed onto the upper lead of the belt 10. A suitableplastic composition 17 in a wet unstable condition, preferably formed ofgypsum, asbestos fiber and water, is deposited on the strip 13 and isspread thereover as the strip advances over the table 15 and passesbetween the forming rollers. A facing and reinforcing strip 18 offibrous foraminous material, such as cotton gauze or netting of openmesh and of a width corresponding to that of the backing strip is fedfrom a roll 19 around and under the upper forming roller 16 and isimpressed by the latter onto the plastic body as itpasses between theforming rollers together with the backing strip 13. The forming rollersare spaced apart and operate .to form the advancing strip 18, plasticbody 17 and foraminous strip 18 into a homogeneous panel ofpredetermined thickness, which passes onto the upper lead of the belt 10and is carried forward by the latter. The upper strip 18 beingforaminous a `portion of the plastic composition will be squeezedltherethrough as it passes between the forming rollers, and accordingly,portions of the composition will adhere to the periphery of the upperroller 16. The wet plastic thus adhering to` the roller 16 is scrapedoff and caused to fall back upon the upper surface of the advancingpanel. The panel is then passed successively between a series of airs ofspaced rollers as indicated at A, B, 4and D, and is thereby subjected toa rolling and pressing action. The pairs of rollers A, B, C, and D arespaced such distance apart and the belt 10 is moved at such speed thatthe plastic composition of the panel will still be wet and unstable asit passes between the end pair of rollers D, although in some 'instancesthe end rollers D may be spaced such distance yfrom the pair of rollersC that the plastic will be partly set on passingn therebetween. The pairof rollers A are spaced apart a distance slightly less than the spacingof the forming rollers 16-16; the pair of rollers B are spaced apart adistance slightly less than the spacing of the rollers A; and the pairof rollers C are spaced apart a distance slightly less than the spacingof the rollers B so that as the panel advances through the series ofpairs ot compressing rollers A, B and C, it is subjected to a series ofsuccessive impressing and rolling actions whereby the solids of theplastic composition are pressed into a more and more compact body. Thiscompressingr action of the rollers A, B and C serves to force the morefluid portion of the plastic to the surface of the plastic body and thuscoats the latter with a rich liquid mixture of gypsum and water whichthickens as the panel advances between the successive pair of rollers.Portions of the liquid will adhere to the peripheries of the upperrollers of the-pairs of rollers A, B and C and is scraped off theserollers and caused to drip back onto the surface of the panel as shownin Figures 3, 4 and 5 so that when the panel passes from between therollers C the top surface of the panel will be formed with a series ofclosely arranged longitudinal extending irregular ribs or ridges 20, asshown in Figures 7 and 8 which ridges will project above the foraminoussheet and will impart a roughened surface to the panel. The final pairof rollers D are employed to flatten the apexes of such ridges 2G as mayproject excessively from the surface of the panel, if so desired; theybeing spaced apart a distance slightly exceeding that of the rollers Cwhere it is desired to flatten the ridges and render them broad, andbeing spaced further apart when it is desired to merely flatten theexcessively high points or portions of the ridges. Where it is desiredto form the board with an exceedingly rough surface the rollers D may bedispensed with or the upper roller of the pair positioned so that itwill not contact the ridges. Such portion of the plastic as may cling tothe uppermost roller of the pair of rollers D is removed therefrom by ascraper as indicated at 2l and may be inhibited from falling backon thesurface of the panel if so desired, it being collected in a troughlformed by the scraper 21 and removed therefrom from time to time asoccasion requires.

The strip of board thus formed is carried forward on the conveyor beltfor such distance and for such length of time that the plastic materialwill set whereupon the strip is trimmed and cut into lengths in anydesired manner to form panels of any desired dimensions which aresubsequently kiln dried whereupon they are in readiness to be employedin forming a wall surface. ln use the panels are nailed or otherwisesecured to a suitable backing or support with the roughened surfaceoutermost, which snrface will have the appearance and character of aplastered wall and mav then be tinished and decorated in any mannerapplicable to the treatment of plastered walls, and

it' desired may be coated with plaster.

By forming the board in the manner set forththe foraminous strip willserve as a screen when the wet unstable plastic com position is passedbetween the several pairs of rollers, to prevent the coarse fibrousconstituents of the plastic composition from ad hering to thecompressing rollers and yet permit a portion of the fluid constituent ofthe plastic composition to pass through thc strip 18 and submerge thelatter which fluid by reason of being Worked by the rollers will berendered rich so that when it scts a hard dense shell will be formed onthe surface ot the board in which the strip will be imbedded. However,the extent of submersion of the foraminous strip 18 in the plasticliquid may be varied as occasion may require, which is accomplished byregulatin the fluidity of the plastic composition an by adjusting thespacing of the compressing rollers. A very desirable surface is obtainedby so submerging the foraminous strip in the main body of the plasticthat the weave of the strip will appear in the depressions formedbetween the raised ridges 2O as shown in Figure 7.

In practice, toform the finished board of a thickness of aboutthree-eightlis of an inch the forming rollers 16-16 are spaced apartabout seven-sixteenths of an inch, and the pairs of rollers A, B and Care spaced respectively thirteen-thirty seconds, threeeighths andeleven-thirty seconds inches apart, while the end rollers D are spacedabout three-eighths of an inch apart.

In the preferred embodiment of the invention a thread-like fibrousmaterial such as asbestos fibers is incorporated in the plasticcomposition so that the ends of some of the fibers will be caused toproject into the interstices formed by the mesh of the foraminous strip18 on pressing the strip onto the plastic, as described, so that thebond between the plastic andthe strip will be increased A 'By workingthe wet plastic body in ,the manner set forth the portion of theplastercarrying the fibrous filler and which extends between the backing sheetVand the forami.- nous sheet will be comparatively soft when dry whilethe outer portion thereof will be formed with a hard shell as beforestated.

While I have shown and described the use of three sets of compressingrollers A, B ard C, it is to be understood that satisfactory results maybe obtained by employing either a lesser or greater number of suchrollers, and that while I have shown and described a specific embodimentof the invention I do not limit myself thereto but reserve the right toall such variations and modifications as properly fall within the scopeof my invention and the terms of the following claims.

I claim l. A Wall board comprising a plaster panel including arelatively soft body formed with a hard surface, and a sheet of nettingembedded in the hard surface portion of the panel through theinterstices of which project and overthe mesh of which netting extendsportions of the plaster; the hard surface of the plaster being formedthroughout with ridges.

2. A plaster board having a fibrous netting on the surface thereofthrough which project bodies of plaster forming the surface of the boardthroughout the entire area thereof with ridges.

3. A wall board comprising a plaster panel, a backing sheet surfacingone side of said panel, and a sheet netting on the other side of saidpanel through which project irregular bodies of plaster forming theboard throughout the area of one side thereof with a roughened surfaceof plaster. j

4. A wall board comprising a panel formed of plaster having the backportion of its thickness formed relatively soft and provided with a hardshell front surface, a fibrous netting on the front surface throughwhich project irregular bodies of the plaster whereby the front surfaceof the board is formed throughout the area thereof with a roughenedsurface of hard plaster, and a backing sheet surfacing the back portionof said panel.

5. The method of forming a plaster board consisting in coating a backingsheet with a wet unstable plastic composition, embedding a sheet ofnetting in the surface of the plastic body under pressure, subjectingthe surface of the plastic body to a rolling and pressing action whilewet so as to squeeze the more liquid content of the plastic compositionthrough the interstices of the sheet, the front surface of the boardbeing formed throughout the area thereof with a roughened surface ofplaster, and then allowing the plastic to set and dry;

6. The method of forming a plaster board consisting in coating a backingsheet with a wet unstable plastic'composition, embedding a foraminoussheet in the surface of the plastic body under pressure, subjecting thesurface of the plastic body to a rollingrv and pressing action while wetso as to cause a thin portion of the plastic to rise through theinterstices of the sheet, removing portions of the thin plastic andcausing such portions to drip back on the surface of the plastic body soas to form ridges thereon, and then allowing the plastic to set and dry.

7. The method of forming aplaster board` consisting in coating a backingsheet with a- Wet unstable plastic composition, embedding a foraminoussheet in the surface of the plastic body under pressure, subjecting thesurfac of 'the plastic body to a rolling and pressing action while wetso as to cause a thin portion of the plastic to rise through theinterstices of the sheet, removing p0rtions of the thin plastic andcausing such portions to drip back on the surface of the plastic body soas to form ridges thereon,

subjecting the ridges to a attening action,

snd then allowing the plastic to set and 8. The method of forming aplaster board consisting in coating a backing sheet with a wet unstableplastic material including in its composition gypsum, fibrous substanceand water; placing a foraminous sheet on the surface of the plasticbody, subjecting the plastic body while soft and wet to a series o fsuccessive impressing and rolling actions to bring a rich fluid mixtureof the ypsum and water to the surface thereof through the foraminoussheet, and allowing the plastic to set and dry.

CHARLES A. PETERS.

